The invention relates to a continuous welding machine for welding facing sides of a pipe blank bent from a material blank with a guide strut for guiding the sides of the pipe blank to be welded to each other in the direction toward a welding device, as well as with pipe guides arranged over the periphery of the guide track for the pipe blank.
Chimney pipes are frequently produced from pipe sections, which each consist of an outer pipe casing and an inner pipe casing, wherein insulation is provided between the outer pipe casing and the inner pipe casing of each pipe section.
To produce the pipe segments needed for the outer pipe casing and the inner pipe casing, various production methods are already known. For example, pipe segments with different diameters can be produced on different production lines, in order to then join them in a final assembly process to form the individual chimney pipe sections.
Here, among other things, continuous welding machines of the type noted above are also used to be able to butt-weld to each other the facing sides of a pipe blank bent from a material blank. In these known continuous welding machines, in the gap of the pipe blank there is a guide strut, in order to be able to guide the sides of the pipe blank to be welded to each other in guide s arranged on opposite sides of the guide strut toward a welding device. Because the guide strut must have a certain minimum thickness for stability reasons, the edges of the pipe blank guided against each other for forming a butt seam are shifted at an angle to each other in such a way that these edges arranged at approximately the same spacing to the guide axis are initially held at a distance by the guide strut, in order to contact only at the weld point arranged before the strut. This guide, which is initially spaced apart on a common peripheral casing, but which then butts against and finally forms an angle for the edges of the pipe blank to be welded to each other, makes it necessary that the pipe blank must be clamped with considerable expenditure of force, in order to be able to press the edges of the pipe blank against each other at an angle to each other at the weld point. Therefore, in these previously known welding machines, pipe guides are needed, which are in a position to press together the edges of the pipe blank that are to be welded to each other and that are initially still spread apart by the guide strut with considerable expenditure of force at the weld point. Known welding machines have special clamping jaws, which can be pressed by contact pressure rollers and which are to be adapted to the desired form of the pipe segment. The adjustment of the known welding machines to a certain pipe diameter of the required pipe blank, however, is associated with considerable retrofitting expense.
If the production options are limited to only one production line, initially a number of pipe segments with one diameter must be produced and temporarily stored, in order to then produce a corresponding number of pipe segments with the other needed diameters. Here, the machines required for forming and welding the necessary pipe segments first have to be converted to the other pipe diameter before pipe segments of such a pipe diameter can be produced on these machines.
The production of pipe segments especially for, if necessary, also quickly changing diameters, therefore requires a considerable amount of time and space. Therefore, a continuous welding machine has also already been created, which is used for welding pre-shaped blanks into pipes (WO 00/29163). The known welding machine has a modular construction and has a support device, which is formed, for example, as a rail and on which several modules are arranged. Here the pre-shaped blank is first inserted into a run-in module, from where the blank can be conveyed further to pre-centering modules. In each of these pre-centering modules, there are loading tools for the blank, which are used for its centering and shaping before the welding module. Now, in order to be able to present the very different pipe dimensions and pipe shapes for welding in a simple way without complicated conversion of the welding machine, it is provided in the welding machine known from WO 00/29163 that along the length of the blank, the modules, which can optionally also be coupled to each other, can be moved from a work position into a waiting position and back on the common support unit.
Because the known welding machine has a modular construction and the individual modules are arranged on a carrier so that they can be exchanged and adjusted relative to each other, an optimum adjustment of the pipe shape to be welded and pipe dimensions should be provided. For example, in WO 00/29163 it is also provided that according to the length of the pipe, several run-in modules and pre-positioning modules can be provided or such modules can be quickly exchanged for adapted modules according to the diameter range of the pipe. By exchanging the centering and welding modules, various welders can also be used in a simple manner. Here, the modules can be shifted on the carrier unit so that they can be brought into an inactive waiting position, in which they do not disrupt the work process of the active module and from which they can be easily brought again into the work position.
In the continuous welding machine known from WO 00/29163, the loading tools provided in the individual modules are stored in the welding machine, in practice, as change tools and activated when needed.
In WO 00/29163 it is described that the known continuous welding machine also has a directional tool, which is to be designated as a guide strut and which is inserted into the still open blank in such a way that the edges of the blank contact the edges of this directional tool extending toward each other. This directional tool, which is pulled upward when the edges of the blank are moved toward each other by the loading tools, should produce a defined position of the edges, so that a butted position of the edges of the blank is formed.
The continuous welding machine known from WO 00/29163 thus represents only a further development of the prior state of the art, which provides different loading tools for adapting to different pipe diameters, wherein these loading tools in WO 00/29163 are provided for shortening or avoiding retrofitting times in the welding machine itself.
Indeed, in WO 00/29163, movement of the guide strut is also provided, but the guide strut is to be raised only when the edges of the blank are to be moved toward each other by the loading tool.